As a substrate processing apparatus of this kind, there is an apparatus that supplies a cleaning gas inside a reaction tube from the nozzle to clean inside the reaction tube and the inner wall of the gas nozzle (for example, Patent Documents 1 and 2). There is another apparatus that supplies a cleaning gas from plural film deposition gas nozzles provided inside the reaction tube (for example, Patent Document 2).    Patent Document 1: JP-A-2000-68214    Patent Document 2: JP-A-2005-286005